How can I encode arbitrary bytes / data in base64 format using Javascript?

Question

For example, let's say I wanted to encode a 64-bit signed integer in base64, how could I (if possible) do this in Javascript?

To clarify, I want to encode the actual bits / bytes of the data, not a string or string representation of the data.

those. the integer 15 in decimal is 0000 1111 in binary, which is Dw == in base64.

I don’t want to encode the string representation of the integer 15. For comparison, if you encode the string “15” in base64, you actually encode 0011 0001 0011 0101, which will give you MTU = in base64 form (this is what window.atob() does window.atob() ).

Answer 1

Convert to a string first, then use btoa or one of the other standard b64 encoders:

 window.btoa(String.fromCharCode(15)); // Dw== 

Answer 2

You can use window.btoa () in browsers that support it, in other browsers you can use this encoder .

- change

You will have to write everything yourself, since everything that you pass to window.btoa is first converted to a string. This answer may be a good place to start; although Gears has been discontinued, many of the related functions are in the HTML5 / W3C File API , which has some experimental implementations .